A race car, moves at a constant speed around an oval track. Is the car accelerating? Why or why not?
3 answers
if it is changing direction, or speed, it is accelerating.
the car accelerates at point b
It is accelerating. Otherwise, it would be moving in a straight line. As long as there's a change in direction, there's acceleration. What we have here is that the magnitude of the velocity (speed) is constant, but the direction keeps changing over time. The only difference between moving at a constant speed around a circle and around an oval track is the constancy of the acceleration: we have constant rate of change in direction (thus velocity) when moving in a circle, and inconstant acceleration when moving in an oval track.